Genady

Because people don't care?

No, not only. You use decimal system here, in your "essential step":

I think that if not for the continent underneath, the ice cover would be even more symmetrical.

Sorry @Mordred, I can't participate. I'm not trained on this level.

It is a Prime Law that all advanced civilizations use ten fingers for counting.

Oh, this is a good trick! +1

Let's go to the next plank under the top two. To stick out without falling these two can have their center of gravity on the edge of the plank under them: This position adds another 0.25m making x = 1 + 1/2 + 1/4 m. How far can we go if we continue like this?

And you are right. +1

OK.

I don't see anything here^^^ that you have hidden.

You haven't mentioned that the decimal system has a special significance in your theory. Does it?

Correct. +1

Hmm ... Except the twin paradox has nothing to do with the Doppler effect. It has to do with the time dilation. The latter is the same regardless of direction of the motion. It depends only on the relative speed between two frames of reference.

What fraction of the bottle is full?

Fixed. Another bottle puzzle:

Will not this work: How to Break a Glass Bottle Safely (ehow.com)?

Like a garbage bag?

It reminded me of a puzzle with two racing bugs. One goes up and down a wall with constant speed. Another goes up, to the same height, with the half speed and then down with the double speed. Who wins? The first bug wins. It is back to the starting point by the time the other one just gets to the top.

Exactly. Intuition without a little arithmetic does a bad job here. +1. (I didn't know about Murphy, and it took me longer to figure it.)

Precisely. +1

A car goes 15 mph for 1 mile. How fast must it go in the same 1 mile back to average 30 mph for the entire round trip? *According to a story, Albert Einstein got this puzzle in a letter from a friend and enjoyed the trick.

I guess, it will be a secret, like the rest of it: